EP3821970B1

EP3821970B1 - Combined flue ozone distribution system

Info

Publication number: EP3821970B1
Application number: EP19834749.4A
Authority: EP
Inventors: Tingyu Zhu; Xindong Wang; Wenqing Xu; Meng Ye; Ruizhuang ZHAO; Zichao JIANG; Bin Wan
Original assignee: Hbis Group Co Ltd; Institute of Process Engineering of CAS
Current assignee: Hbis Group Co Ltd; Institute of Process Engineering of CAS
Priority date: 2018-07-12
Filing date: 2019-02-28
Publication date: 2023-07-26
Anticipated expiration: 2039-02-28
Also published as: EP3821970A1; EP3821970A4; CN108905555A; WO2020010851A1; CN108905555B; KR20210029817A; KR102563270B1

Description

This application claims priority to Chinese Patent Application No. 201810763514.0 titled "Combined Flue Ozone Distribution System" filed Jul. 12, 2018 .

TECHNICAL FIELD

The present application relates to the technical field of environmental engineering, for example, specially to a combined flue ozone distribution system1.

BACKGROUND

NO, which accounts for more than 90% of NOx in flue gas, is hard to remove because NO is quite insoluble in water, while NO₂ and SO₂ have similar properties, and NO₂ and SO₂ are both acid gas and are freely soluble in water, which means that NO₂ and SO₂ can be easily removed by reacting with alkaline substances. Therefore, for the purpose of denitration, it is necessary to first oxidize NO to NO₂ and then remove it.
Many different technologies have been developed for NO oxidation removal, among which the low-temperature ozone oxidation and denitration technology refers to injecting O₃ into flue before the flue gas enters the purification device to oxidize NO to NO₂, and then the gas enters the subsequent absorption section. The patent with the application number CN201610272778.7 discloses an ozone low-temperature oxidation and denitration process and system. The technical solution is to install an ozone generator in the flue, spray ozone into the flue through an ozone distributor, and then send the mixture of ozone and flue gas into scrubbing tower to remove nitrogen oxides. The patent with the application number CN201610202410.3 discloses an ammonia oxidation and denitration process and reaction apparatus. In this technical solution, ozone oxidation and hydrogen peroxide oxidation of flue gas are combined in an orderly manner, and the ozone-oxidized flue gas is further absorbed by alkalescent absorption solution, and absorb the hydrogen peroxide-reoxidized flue gas by acidulous absorption solution, thereby eliminating the emission and pollution of nitrogen oxides. It can be seen from the published patent reports that using Os to oxidize NO in a gas phase is an effective oxidation technology.
However, it should be noted that Os is very unstable, and it decomposes slowly at room temperature and decomposes rapidly at 200°C. Thus, the dispersion effect of Os and the effect of contact between Os and NO in a flue directly determine the oxidation efficiency and subsequent absorption effect of NO, and therefore the mixing effect of the two gases has become the focus of development of low-temperature ozone oxidation and denitration technology. Accordingly, the development of ozone distributors which affect gas flow distribution in the flue has becomes hot spot.
Document CN 107 774 109 A discloses an apparatus in accordance with the preamble of claim 1.

SUMMARY

The present application provides a combined flue ozone distribution system, which has the advantages such as good distribution effect, stronger working condition adaptability, and greater operation flexibility.
A combined flue ozone distribution system includes a first ozone distributor and a second ozone distributor that are disposed in a flue. The first ozone distributor and the second ozone distributor each includes a plurality of main distribution pipes, a plurality of branch distribution pipes, and connecting pipes configured to supply ozone. Both sides of each main distribution pipe are each provided with a branch distribution pipe. The first end of one main distribution pipe (4) is communicated with a connecting pipe, and the second end of the one main distribution pipe (4) is communicated with a branch distribution pipe. The first ozone distributor also includes hemispherical distributors, and one hemispherical distributor is disposed at an end of one branch distribution pipe of the first ozone distributor. The second ozone distributor further includes rhombic guide plates, and one rhombic guide plate is disposed at an end of the one branch distribution pipe of the second ozone distributor.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a front view of a first ozone distributor according to an embodiment of the present application.
FIG. 2 is a front view of a second ozone distributor according to an embodiment of the present application.
FIG. 3 is a schematic view illustrating the structure of a hemispherical distributor of a first ozone distributor according to an embodiment of the present application.
FIG. 4 is a schematic view illustrating the structure of a rhombic guide plate of a second ozone distributor according to an embodiment of the present application.

Reference list

100: first ozone distributor
200: second ozone distributor
300: flow regulating valve
1: flue
2: connecting pipe
3: flange
4: main distribution pipe
5: branch distribution pipe
6: hemispherical distributor
7: rhombic guide plate
10: via

DETAILED DESCRIPTION

The main function of ozone distributor in flue is to improve the mixing uniformity of ozone and flue gas injected into the flue and to improve the oxidation efficiency of NO in the flue gas by ozone, so that NO is oxidized to NO₂ to the greatest extent before entering purification device, thereby ensuring denitration efficiency. The design of the ozone distributor is adjusted and optimized based on ammonia injection grid, so that besides the original advantages, such as high mixing uniformity, the ozone distributor has stronger adaptability. Patent CN103877837B and patent CN201410059167.5 discloses a flue ozone distributor used in low-temperature oxidation and denitration technology and its arrangement in the flue respectively. The ozone distributor is simple in structure, is easy in assemble and disassemble, and is easy in clean. Moreover, the ozone distributor enables ozone to be distributed uniformly on cross section of the flue, and has been applied in engineering practice.
As shown in FIGS. 1 to 4, embodiments provide a combined flue ozone distribution system. The combined flue ozone distribution system includes a first ozone distributor 100 and a second ozone distributor 200 disposed in a flue 1. The first ozone distributor 100 and the second ozone distributor 200 each includes a plurality of main distribution pipes 4. Two sides of each main distribution pipe 4 are each provided with a branch distribution pipe 5. The first end of one main distribution pipe 4 communicates with a connecting pipe 2 for supplying ozone, and the second end of the one main distribution pipe 4 communicates with a branch distribution pipe 5. The end of the branch distribution pipe 5 of the first ozone distributor 100 is provided with one hemispherical distributor 6. The end of the branch distribution pipe 5 of the second ozone distributor 200 is provided with one rhombic guide plate 7.
The combined flue ozone distribution system according to the embodiments using a first ozone distributor 100 and a second ozone distributor 200 which are disposed in the flue 1. The first ozone distributor 100 and the second ozone distributor 200 are perpendicular to the flow direction of flue gas. The first ozone distributor 100 and the second ozone distributor 200 are disposed in order following the flow direction of the flue gas. The first ozone distributor 100 is configured to inject and disperse ozone and uses a structural form in which multiple branch distribution pipes 5 and multiple hemispherical distributors 6 are disposed in the same plane. In engineering application, the coverage and uniformity of ozone on the section of the flue 1 are ensured by adopting this structure. The second ozone distributor 200 is configured to inject ozone again and increase the disturbance of the mixture of ozone and flue gas. Similarly, the second ozone distributor 200 uses a structural form in which multiple branch distribution pipes 5 and multiple rhombic guide plates 7 are disposed in the same plane. In engineering application, this structure ensures the coverage of ozone on the section of the flue 1, and the rhombic guide plate 7 is arranged perpendicular to the axis of one branch distribution pipe 5 so as to enhance the disturbance of flue gas and ozone, improve the mixing effect of mixture gas on the horizontal section, shorten the time of ozone mixing in flue gas, and increase the effective utilization of ozone, thereby increasing the oxidation rate of NO.
In an embodiment, the specific form and size of each component can be selected according to the actual need. The distance between main distribution pipes, between branch distribution pipes and between the first ozone distributor 100 and the second ozone distributor 200 can be selected according to the actual need. In the embodiment, the materials of the components of the combined flue ozone distributors can be determined according to the environmental condition in practical application.
In an embodiment, the second ozone distributor 200 is installed behind the first ozone distributor 100 along the flow direction of flue gas, and the distance between the second ozone distributor 200 and the first ozone distributor 100 is 700 mm to 1000 mm. In addition, the distance between the second ozone distributor 200 and the first ozone distributor 100 can be determined according to the environmental conditions of the installation site, for example, 820 mm to 830 mm, 900 mm to 910.5 mm, or 960 mm to 968 mm may be selected. In an embodiment, the distance between the second ozone distributor 200 and the first ozone distributor 100 is 850 mm to 950 mm.
In the first ozone distributor 100 or the second ozone distributor 200, the connecting pipe 2 is provided with a flow regulating valve 300 with strong adaptability which can adjust ozone intake quantity according to the NO concentration in flue gas. The connecting pipe 2 communicates with the main distribution pipe 4 to ensure that the ozone enters the subsequent gas path smoothly.
The connecting pipe 2 communicates with the main distribution pipe 4 through the flange 3, and a plurality of flanges 3 are arranged in parallel in the same plane. The distance between two adjacent main distribution pipes 4 is 500 mm to 600 mm, for example, 510.3 mm to 525 mm, 528 mm to 560.5 mm, or 578 mm may be selected. In an embodiment, the distance between two adjacent main distribution pipes 4 is 510 mm to 560 mm.
In the first ozone distributor 100 or the second ozone distributor 200, on the same side of each main distribution pipe 4, the distance between two adjacent branch distribution pipes 5 is 230 mm to 330 mm, for example, 235.8 mm to 276.3 mm, 240 mm to 255 mm, or 280 mm may be selected. In an embodiment, in the first ozone distributor 100 or the second ozone distributor 200, on the same side of each main distribution pipe 4, the distance between two adjacent branch distribution pipes 5 is 260 mm to 310 mm.
The axis of one branch distribution pipe 5 is perpendicular to the flow direction of flue gas. The inner surface of the hemispherical distributor 6 is provided with a plurality of vias 10. The diameter of one hemispherical distributor 6 is equal to the diameter of one branch distribution pipe 5. One branch distribution pipe 5 communicates with a plurality of vias 10 of one hemispherical distributor 6. The pore size of one via 10 is 37 mm to 39 mm, for example, 37.5 mm to 38.5 mm or 38.9 mm may be selected. The inner surface of one hemispherical distributor 6 is provided with three circles of vias 10. The flow rate of ozone in the vias 10 is 20 m/s to 25 m/s, for example, 20.5 m/s, 23.8 m/s, or 24.5 m/s. In an embodiment, the flow rate of ozone in the via 10 is 22 m/s to 24 m/s. In an embodiment, as shown in FIG. 3, the vias 10 are distributed in two circles on the inner surface of the hemispherical distributor 6, and one via 10 is disposed at the center of the inner surface of the hemispherical distributor 6.
In the second ozone distributor 200, one rhombic guide plate 7 is perpendicular to the axis of one branch distribution pipe 5, the long axes of each two adjacent rhombic guide plates 7 are perpendicular to each other, and the length of one side of one rhombic guide plate 7 is 60 mm to 100 mm, for example, 65.5 mm to 80 mm, 70 mm to 75.8 mm, or 80 mm. In an embodiment, the length of one side of one rhombic guide plate 7 is 75 mm to 85 mm. The gas velocity of one rhombic guide plate 7 is controlled to be 20 m/s to 25 m/s, for example, 20.2 m/s, 22.6 m/s, or 24.0 m/s may be selected. In an embodiment, the gas velocity of one rhombic guide plate 7 is 22 m/s to 24 m/s.
In the embodiments, the diameter of the main distribution pipe 4 and the diameter of the branch distribution pipe 5 are determined according to the gas velocity (that is, the flow rate of ozone).
The flue ozone distributors are applicable to the ozone low-temperature oxidation and denitration system in coal-fired power plants, steel and other industries. The installation, cleaning and maintenance of the flue ozone distributors are easy and convenient. The direction in which ozone is injected into the flue 1 is perpendicular to the flow direction of flue gas to avoid ash accumulation and blockage. In addition, ozone intake can be adjusted according to NO concentration in flue gas; thus, the flue ozone distributors have great advantages in engineering application with high flexibility and strong operability.

Claims

A combined flue ozone distribution system, comprising a first ozone distributor (100) and a second ozone distributor (200) that are disposed in a flue (1),
wherein the first ozone distributor (100) and the second ozone distributor (200) each comprises:
a plurality of main distribution pipes (4), a plurality of branch distribution pipes (5), and

connecting pipes (2) configured to supply ozone, wherein both sides of each of the plurality of main distribution pipes (4) are each provided with a branch distribution pipe (5), a first end of one of the plurality of main distribution pipes (4) is communicated with a connecting pipe (2), and a second end of the one of the plurality of main distribution pipes (4) is communicated with a branch distribution pipe (5),

characterized in that

the first ozone distributor (100) further comprises hemispherical distributors (6), and one of the hemispherical distributors (6) is disposed at an end of the one of the plurality of branch distribution pipes (5) of the first ozone distributor (100); the second ozone distributor (200) further comprises rhombic guide plates (7), and one of the rhombic guide plates (7) is disposed at an end of the one of the plurality of branch distribution pipes (5) of the second ozone distributor (200).
The combined flue ozone distribution system of claim 1, wherein the first ozone distributor (100) and the second ozone distributor (200) are arranged perpendicular to a flow direction of flue gas, and the first ozone distributor (100) and the second ozone distributor (200) are distributed in sequence along the flow direction of the flue gas.
The combined flue ozone distribution system of claim 1, wherein an axis of the one of the plurality of branch distribution pipes (5) is perpendicular to a flow direction of flue gas, and an inner surface of the one of the hemispherical distributors (6) is provided with a plurality of vias (10).
The combined flue ozone distribution system of claim 3, wherein in the first ozone distributor (100), a diameter of the one of the hemispherical distributors (6) is equal to a diameter of the one of the plurality of branch distribution pipes (5), and the one of the plurality of branch distribution pipes (5) is communicated with the plurality of vias (10) of the one of the hemispherical distributors (6).
The combined flue ozone distribution system of claim 4, wherein the plurality of vias (10) of the one of hemispherical distributors (6) are arranged in three circles on the inner surface of the one of hemispherical distributors (6), and the system is configured such that a flow rate of ozone in the plurality of vias (10) is within a range from 20 m/s to 25 m/s.
The combined flue ozone distribution system of claim 1, wherein in the second ozone distributor (200), the one of the rhombic guide plates (7) is perpendicular to an axis of the one of the plurality of branch distribution pipes (5), long axes of each two adjacent ones of the rhombic guide plates (7) are perpendicular to each other, and a length of one side of the one of the rhombic guide plates (7) is within a range from 60 mm to 100 mm.
The combined flue ozone distribution system of claim 1, wherein a distance between the first ozone distributor (100) and the second ozone distributor (200) is within in a range from 700 mm to 1000 mm.
The combined flue ozone distribution system of claim 1, wherein the first ozone distributor (100) or the second ozone distributor (200) comprises a flow regulating valve (300) and flanges (3), the connecting pipes (2) in the first ozone distributor (100) or the second ozone distributor (200) are respectively provided with the flow regulating valve (300), and one of the connecting pipe (2) in the first ozone distributor (100) or the second ozone distributor (200) is communicated with the one of the plurality of main distribution pipe (4) through one of the flanges (3).
The combined flue ozone distribution system of claim 1, wherein a distance between each two adjacent ones of the plurality of main distribution pipes (4) in the first ozone distributor (100) or the second ozone distributor (200) is within a range from 500 mm to 600 mm.
The combined flue ozone distribution system of claim 1, wherein in the first ozone distributor (100) or the second ozone distributor (200), a distance between two adjacent ones of the plurality of branch distribution pipes (5) on a same side of the one of the plurality of main distribution pipes (4) is within a range from 230 mm to 330 mm.